package day0212;

import java.util.Scanner;

public class Test2 {
    public static void main(String[] args) {
        Scanner s=new Scanner(System.in);
        int n2=s.nextInt();
        for (int i = 1; i <= n2 ; i++) {
            n2=n2*i;
        }
        System.out.println(n2);
    }
}
